The primary objective of the research in progress is to determine if the red cells from newborn infants behave differently than the red cells of normal adults under conditions of reduced oxygen tension that simulate the intrauterine environment. In the first year of study it was found that glucose consumption and red cell lactate production increased with hypoxemia but not as dramatically in the newborn. In addition, it was found that the vulnerability to oxidant compounds was markedly diminished at low oxygen tensions.